1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) panel and a manufacturing method for the same, and more particularly, to a color filter on array (COA) substrate and a manufacturing method for the same.
2. Description of the Prior Art
An advanced monitor with multiple functions is an important feature for use in current consumer electronic products. Liquid crystal displays (LCDs) which are colorful monitors with high resolution are widely used in various electronic products such as monitors for mobile phones, personal digital assistants (PDAs), digital cameras, laptop computers, and notebook computers.
A conventional LCD panel comprises a color filter substrate, a thin film transistor array substrate (TFT array substrate), and a liquid crystal layer disposed between the color filter substrate and the TFT array substrate. However, the conventional LCD panel has disadvantages of a worse resolution, a lower aperture ratio of a pixel, and a misalignment which easily occurs when the color filter substrate joints the TFT array substrate.
In recent years, a new LCD panel is provided. The color filter layer is integrated into a color filter on array (COA) substrate placed on the TFT array substrate. The COA substrate and an opposite substrate which does not comprise a color filter layer are assembled. Liquid crystals are inserted into a domain between the COA substrate and the opposite substrate, which is the structure of the new LCD panel. Since the color filter layer is directly formed on the TFT array substrate, no misalignment could occur to the LCD panel. Furthermore, the LCD panel has advantages of a better resolution and a higher aperture ratio of the pixel.
The process of the conventional COA substrate comprises the steps of; first, forming a TFT matrix on a substrate; secondly, depositing a color filter, a transparent conducting layer, and an alignment film successively on the substrate for forming the COA substrate; thirdly, deposing liquid crystals on the COA substrate; finally, adhering an opposite substrate to the COA substrate using a sealant disposed around the periphery of the first substrate. An LCD panel is formed accordingly.
A passivation layer covering a drain of the TFT needs etching for forming a via so that the drain which is turned on could be connected to the transparent conducting layer. To prevent the displaying effects of the LCD panel from being affected, the thickness of the color filter is about ten times of the thickness of the drain. However, the lateral wall of the via is slanted at an angle of close to 90 degrees because of the difference of the thickness between the color filter and the drain, which hinders the transparent conducting layer from being deposited on the via. Moreover, electro static discharge (ESD) may occur on the LCD panel.